Mounting for burrs



sept, 28,1926. v y 1,601,454

F. W. ROBERTS MOUNTING FOR BURRS Filed March 2, 1923 Patented Sept. 28, 1926.

UNITED STATES PATENT OFFICE.

FREDERICK W. ROBERTS, OF LOCKPORT, NEW YORK, ASSIGNOR TO F. W. ROBERTS MANUFACTURING COMPANY, INC., OF LOCKPORT, NEW YORK.

MOUNTING FOR BURRS.

Application filed March 2, 1923. Serial No. 622,442.

This invention relates to burrs for use Vin dressing grindstones, and more particularly to the means for mounting theburrs on their spindles or on their bearing sleeves. The burr mounting is primarily intended for use in connection with wood pulp grindstones.

Heretofore cylindrical or shell burrs for dressing Wood pulp grindstones have been mounted on cores, clamps or chucks of various kinds which in turn were rotatably supported on a spindle, the endsr of which were held in a burr holder, and the cores, clamps or chucks were always of heavy or massive construction so that practically the entire space between the shell burr and the bearing spindle was filled with metal. Consequently a mass of metal considerably greater than the burr itself, as well as the burr must be brought to a high speed of rotation by contact between the faces of the burr and grindstone, and the inertia of this mass of metal causes the rapidly revolving stone to grind off a` considerable portion of the teeth of the burr each time that the burr is used, before the burr is brought to rotate at the same peripheral speed as the grindstone. Also the rigidi-ty of the mass of metal between the burr and the bearing sleeve or spindle causes a great deal of vibration which is not only injurious to the lathe by means of which the burr is moved along and pressed against the surface of the grindstone, but also produces a more or less rough or uneven cut in the stone which has a detrimental effect on the pulp produced.

The objects of this invention are to provide means of improved construction for mounting cylindrical or shell burrs on a bearing sleeve, which means are light in weight so that the inertia of the burr mounting will be much less than those heretofore used; also to provide'means for mounting a burr of this kind on a bearing sleeve in such a manner that there will be some resilience between the burr and its sleeve; also to improve in other respects hereinafter specified the means for mounting'burrs of this kind on their bearing sleeves.

In the accompanying drawings:

Fig. l is a face view of a burr arranged on a holder and provided with means embodying the invention for mounting a burr on its spindle.

Fig. 2 is an end elevation thereof on an wood enlarged scale with the burr holder and .spindle omitted.

Fig. 3 is a central sectional view thereof on line 3 3, Fig. 2.

Fig. 4- is a transverse sectional view thereof on line 4 4, Fig. 3.

Fig. 5 is anfend view of a burr provided with another form of mounting.

Fig. 6 is a longitudinal sectional View thereofon line 6 6, Fig. 5.

A represents a. cylindrical or shell burr of the kind commonly used for dressing pulp grindstones,4 the burr having on its outer periphery a number of teeth or projecti'ons which are adapted to enter into the cylindrical surface of the stone to dressthe same. The burr is shown in Fig. 1 as mounted on the usual burr holder B having 'an outer bifurcated portion through which a bearing pin or spindle B extends, on which the burr is journalled. All of these lparts have heretofore been used in connection with the dressing of grindstones and of themselves constitute no part of this invention. Y

In burrs as heretofore made, the space between the bearing spindle and the shell burr was usually either entirely or partially filled with a core, chuck, clamping member, or analogous metal part for mounting or centering the burr on the bearing spindle. This invention aims to replace the heavy metal clamps, chucks, cores or the like heretofore used, by supporting or mounting means of light weight and preferably, though not necessarily, of slightly resilient nature so that when the burr mounted on its holder is pressed against the face of the grindstone, there will be comparatively little inertia to overcome, and consequently lthe burr will be quickly brought up to the same peripheral speed as a grindstone and with but little grinding of the burr by the grindstoni.y It

' is also desirable to make the burr mounting slightlyresilient to absorb many of the vibrations to which burrs as heretofore made are subjected. It is necessary that vthe resiliency of the mounting means be only sufficient to absorb the vibrations to which the burr is subjected by contact with the stone,

but the burr must not yield sufficiently to make it possible for the cylindrical surface of the stone to become eccentric or to develop high spots, due to hard portions in the stone. lt has, for example, been found that a burr mounting having a maximum deflection of three hundredths of an inch absorbed the greater part of the vibrations of the burr and at the sane time kept the surface of the stone truly cylindrical. It is not, of course, intended to limit this invention to the maximum deflection specified, since equally goed results may be produced by burr mountings having greater or less resiliency, and furthermore, the permissible 'or desired resiliency may vary with different Igrades of grindstones. My invention may be carried out by various constructions, some of which are herein illustrated.

ln the construction shown in Figs. 1 4, the means heretofore used for mounting the shell burr on the bearing spindle are replaced by a bearing sleeve C which is adapted to cooperate with the spindle B to form a bearing for the burr. The burr is supported on the bearing` sleeve by means of a plurality of stamped metal members D, each of which, in the particular construction shown, is made from a strip of metal and includes outer burr-engaging portions CZ which are preferably angle-shaped so as to engage the end face and a` part of the inner face of the shell burr, a central body portion d', which in the construction shown bears against the bearing sleeve C, and connecting` portions Z2 which extend from the ends of the body portion to the burr-engaging portions Z and which consequently bridge the space between the bearing member and the burr. In order to securely hold these stamped members in place, the outer face of the bearing sleeve is preferably made polygonal, being shown hexagonal in the construction illustrated, and consequently six stamped metal members D are used, the body portions d of which bear against the sides of the bearing member C. Any suitable ,nr desired means may be employed for holding the stamped metal members in place on the bearing member, retaining washers E being provided for this purpose, in the construction shown. These washers are adapted to tit snugly on cylindrical end portions e of the bearing member C and the outer peripheries of the washers, in the construction shown, are hexagonal iii form. lf desired, theest-amped metal members may be provided with corner-shaped portions d3 at the ends of the body portions d and which rest on the sides of the washers E. The washers may be held in place on the bearing member in any desired manner, split spring rings e being provided for this purpose, which are adapted to seat in grooves in the cylindrical end portions e of the bearing member E. rliese split rings securely hold the washer on the bearing member and at the same time make it possible to remove the washer, and consequently the stamped members D, from the bearing member so that the cylindrical burr when worn out can be replaced by another burr. The stamped members D are preferably made of steel and consequently possessthe desired ldegree of resiliency. yThe members are also light in weight and add very little to the inertia. of the shell burr.v

ln theconstruction shown in Figs. 5 and 6, l represents the burr and K the bearing sleeve which'may beof polygonal form having cylindrical end portions 7c of reduced diameter. In this construction, the burrs are spaced with reference to the bearing sleeve by means of a pair of disks L, the outer ends Z of which are adapted to engage the opposite end faces or annular edge portions ofthe burr l, and the innerportions of which are provided with polygonal apertures into which the bearing sleeve K may extend,the disks being preferably provided with flange portions Z engaging the outer polygonal portion of the bearing sleeve l. The disks may be held in place on the bear- ,J sleeve in any suitable or desired manner, for example by means of washers lvl which may also be polygonal in shape and have central apertures through which may be inserted the cylindrical end portions /i of the bearing sleeve, and split sgring rinffs vm,

similar to those described in connection with 'l Figs. 1%, may be used for holdingl the washers in place on the bearing sieeve.`

These disks are also light in weight and alford suflicient resiliency to avoid the i pirious vibrations which have heretofore been yfound so destructive to the life of lathes used in connection with the facing of grindstones and to t-lie surfaces of the grindstoiies.

The means for mounting the burrs on their spindles which have been described,

have the advantage of greatly increasing the life of the burr due mainly to the fact that there is comparatively little grinding action during the time that. the burr is brought from the standstill to the peripheral speed of the grindstone, and due to the 'fact thatvthe decrease in vibration decreases the destructive action on the burr and stone as well as to the lathe on which the burr is held. By marking the buiU mountings of Ylighter weight, the burrs are much easierA to handle in the inaccessible. and awkward places under the pulp grindstones in which these burrs must be changed from time to time to place a new burr on the dressing lathe. The operative who changes these burrs is working under considerable difficulties, due to the inaccessibility of the ltlll mounting described also has the advantage that the burr and mounting can be secured on the bearing sleeve in the factory or shop in which the burr is made, since the bearing sleeve and mounting add very little to the weight of the burr, whereas heretofore the mount-ing means, such as cores, chucks or the like, were so heavy that it was impractical to ship all burrs ready mounted on their sleeves, and consequently the work of Y mounting the burrs on the bearing mem bers had to be done in the pulp mill where skilled mechanics are not ordinarily available. Pulp grindstones are more uniformly dressed by burrs provided with the mountings described and thus produce a more uniform grade of wood pulp, and by greatly reducing the grinding action on the burrs while they are being brought up to the peripheral speed of the grindstones, the life of the burrs is greatly increased.

I claim as my invention:

l. The combination of a cylindrical burr Yfor dressing grindstones for grinding pulp wood, a bearing sleeve arranged within the burr, and sheet metal members secured to and forming the only connection between said sleeve and said burr, said sheet metal members being of light weight so that the combined inertia of said burr and said members is small, whereby the burr can attain the peripheral speed of the grindstone with a small amount of abrasion or' the burr.

2. The combination of a cylindrical burr for dressing grindstones for grinding pulp wood, a bearing sleeve arranged within the burr, and a metallic connection between said burr and said sleeve, comprising sheet metal members connecting the edge portions only of said burr with said sleeve and forming the only connection between said burr and said sleeve whereby the inertia of the burr is small.

3. rThe combination of a cylindrical burr for dressing grindstones for grinding pulp wood, a bearing sleeve arranged within said burr, and relatively light weight metal members connecting the edge portions only of said burr and said sleeve to hold said burr in operative relation to said sleeve, the weight and inertia of said burr, said connecting members and said sleeve being small to reduce the grinding off oi the teeth of the burr while the same is being rotated by contact with the grindstone from a stand still to the peripheral speed of the grindstone.

4. The combination of a cylindrical burr for dressing grindstones for grinding pulp wood, a bearing sleeve arranged within said burr, sheet metal members arranged at the sides or' said burr and having their outer portions shaped to engage the edge portions of said burr and having their inner portions engaging said sleeve, and means on said bearing sleeve for holding said sheet metal members on said sleeve and in gripping engagement with said burr.

5. The combination of a cylindrical burr for dressing grindstones for grinding pulp wood, a bearing sleeve arranged within the burr, a plurality of sheet metal members connecting said sleeve and having parts which frictionally engage the edge portions of said burr, washers mounted on said sleeve and holding said sheet metal members in operative relation thereto and to said burr, and means for releasably holding said washers on said sleeve.

6. The combination of a cylindrical burr for dressing grindstones for grinding pulp wood, a bearing sleeve arranged within the burr, a plurality of sheet metal members connecting said sleeve and having their outer edges shaped to frictionally engage the opposite edge portions of said burr, washers mounted on said sleeve and holding said sheet metal members in operative relation thereto and to said burr, and split spring rings seated in grooves in said sleeve for holding said washers in place on said sleeve.

FREDERICK W. ROBERTS. 

